So scan line 1 is 2500. However I still don't know where the other scan lines (2,4,6,8) are in Unicode... This is really not well explained.

I committed 23BA-23BD based on 2500... Not clear what the application is.

Likewise with the other brackets. The application is quite unclear. How is such an assembled character meant to interact with other characters on a line? Strange, since Unicode is explicitly meant to represent in-line text (as opposed to two-dimensinal notations such as western music).

⎰ = U+23B0 UPPER LEFT or lower right bracket section
⎱ = U+23B1 upper right or LOWER LEFT bracket section
Both one atop the other as above form a left curly bracket
⎱ = U+23B1 UPPER RIGHT or lower left bracket section
⎰ = U+23B0 upper left or LOWER RIGHT bracket section
Both one atop the other as above form a right curly bracket

⎲ = U+23B2 summation top
⎳ = U+23B3 summation bottom
Both one atop the other as above form a big U+2211 N-ARY SUMMATION

For scan lines, these are characters found in VT100 and similar terminals, where there are only 9 scan lines to draw characters. See the pictures at http://vt100.net/dec/vt220/glyphs, these are the five characters at the top of the second column. So scan line-1 is at the top, scan line-9 at the bottom, and scan line-5 is really U+2500.